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United States Patent |
5,613,902
|
Didion
,   et al.
|
March 25, 1997
|
Sand reclaimer
Abstract
A tumbling mill includes an inlet area, an outlet area, and a tumbling area
between the inlet and outlet areas. The mill is formed as a tri-cyclical
member having an outer cylinder extending along the tumbling and outlet
areas, and an inner cylinder concentric with the outer cylinder and
extending through the inlet, outlet and tumbling areas. The inner and
outer cylinders define a space therebetween. The inner cylinder is
perforated to allow sand to fall into the space between the inner and
outer cylinders. The inner cylinder includes an inner helical vane to urge
sand, media, and castings toward the outlet area, and an outer helical
vane to urge sand and media toward the inlet area. A reclassifying screen
is provided in the inlet area to classify sand. Sand particles that are
sufficiently small passes through the screen and out a chute. Sand
particles that are not small enough are recirculated through the tumbling
mill to be further broken down. A shell is positioned in the inlet area
between the inner cylinder and the screen to hold the segments which form
the inner cylinder together under heavy tumbling. The shell includes a
plurality of relatively large openings to allow any sand that falls enters
the shell to fall through to the screen. A third helical vane is
positioned between the shell and the screen. Preferably, the edges of the
third helical vane are aligned with the openings in the shell. The shell
is sufficiently thick (preferably between 3/8" to 1") to prevent said
segments from separating under pressure of extensive tumbling.
Inventors:
|
Didion; Michael S. (St. Charles County, MO);
Didion; Charles J. (St. Charles County, MO)
|
Assignee:
|
Didion Manufacturing Company (St. Peters, MO)
|
Appl. No.:
|
621090 |
Filed:
|
March 25, 1996 |
Current U.S. Class: |
451/326; 164/404; 209/292; 241/79.3; 241/DIG.10; 451/104; 451/113; 451/328 |
Intern'l Class: |
B22D 029/00 |
Field of Search: |
451/104,105,113,326,328,330
209/292
241/79.3,DIG. 10
|
References Cited
U.S. Patent Documents
2050458 | Aug., 1936 | Ovestrud et al.
| |
3862719 | Jan., 1975 | Muller.
| |
3998262 | Dec., 1976 | Didion.
| |
4050635 | Sep., 1977 | Mueller et al.
| |
4137675 | Feb., 1979 | Cina et al. | 451/328.
|
4674691 | Jun., 1987 | Didion.
| |
4981581 | Jan., 1991 | Didion.
| |
5016827 | May., 1991 | Didion.
| |
5095968 | Mar., 1992 | Didion.
| |
5267603 | Dec., 1993 | Didion.
| |
Foreign Patent Documents |
0607650 | Jul., 1994 | EP.
| |
0129120 | Nov., 1978 | JP.
| |
0084667 | May., 1983 | JP.
| |
Primary Examiner: Little; Willis
Assistant Examiner: Morgan; Eileen P.
Attorney, Agent or Firm: Denk; Paul M.
Claims
I claim:
1. A tumbler for use in separating surface disposed core sand from fresh or
dirty castings by tumbling said castings in the presence of abrasive
members, said rambler comprising:
an inlet area, an outlet area, and a tumbling area between said inlet and
outlet areas;
an outer cylinder extending along said tumbling and outlet areas;
an inner cylinder concentric with said outer cylinder and extending through
said inlet, outlet and tumbling areas, said inner cylinder and outer
cylinder defining a space therebetween, said inner cylinder being
perforated to allow sand to fall into said space between said inner and
outer cylinder; said inner cylinder including an inner helical vane to
urge sand, media, and castings toward said outlet area, and an outer
helical vane to urge sand and media toward said inlet area;
a shell in said inlet area, said shell having an inner diameter
approximately equal to the diameter of said outer helical vane, said shell
defining a plurality of openings therein through which sand and media may
fall; and
a perforated screen surrounding said shell, said screen perforations being
sized to allow sand particles of a desired size to fall therethrough, said
screen being supported about said shell by a third helical vane.
2. The tumbler of claim 1 wherein edges of said third helical vane are
aligned with said openings in said shell.
3. The tumbler of claim 2 wherein said inner cylinder comprises a plurality
of interconnected segments; said shell being sufficiently thick to prevent
said segments from separating under pressure of extensive tumbling.
4. The tumbler of claim 3 wherein said shell is made of 3/8" to 1" sheeting
.
Description
BACKGROUND OF THE APPLICATION
This invention relates generally to a tumbling mill for new castings, and
in particular to a tumbling mill with improved sand reclaiming abilities.
Various types of tumbling devices or mill for removing mold sand from
casting, or for separating other particles or fragments from castings or
other metal parts have long been available in the art. For example, my
prior patent, U.S. Pat. No. 4,674,691, which is incorporated herein by
reference, discloses a tumbler including a sand reclaimer which will
return sand and media from the outlet area of the tumbler to the inlet
area, where the media can be reintroduced into the tumbler. In my prior
patent, U.S. Pat. No. 5,267,603, which is also incorporated herein by
reference, I disclose another tumbler, which also includes a media and
sand return system. This tumbler, however, is provided with a screen
classifier which will allow small particles of sand to fall through a
screen. The screen is provided at the inlet area of the tumbler and is
housed in a casing. The sand which passes through the screen exits the
tumbler through a chute in the housing. The screen surrounds the segmented
inner liner and thus performs two functions: (1) it screens the sand so
that small particles of sand will fall through and so that media and
larger particles of sand will be reintroduced into the tumbler; and (2) it
holds the segmented liner together in the intake area of the tumbler.
The segments are interlocked with each other, as described in my
application Ser. No. 08/323,010, which is incorporated herein by
reference. However, when a large number of heavy castings, such as engine
block castings, are introduced into the tumbler, the tumbling of the
castings within the unit may cause the segments to separate, either
radially or horizontally. This can lead distorting of the screen.
Eventually, the screen will have to be replaced, so that the intake
section will be able to be held together.
SUMMARY OF THE INVENTION
One object of the present invention is to provide an improved sand
reclaiming casting shake out unit or tumbler.
Another object is to provide finer sand screening whereby the openings in
the final screen are now smaller than the openings in the liner segments.
Another object is to provide such a tumbler in which the inner liner of the
tumbler is securely held together in a cylindrical fashion.
Another object is to enable the machine to breathe easier due to the
increase in the screen open area.
Yet another object is to prevent blinding in the woven wire screen versus
the larger punched slot in the main drum.
These and other objects will become apparent to those skilled in the art in
light of the following disclosure and accompanying drawings.
In accordance with the invention, generally stated, a tumbling mill formed
as a tri-cyclical type is provided. The tumbling mill includes an inlet
area, an outlet area, and a tambling area between the inlet and outlet
areas, an outer cylinder extending along the tumbling and outlet areas,
and an inner cylinder concentric with the outer cylinder and extending
through the inlet, outlet and tumbling areas. The inner and outer
cylinders define a space therebetween. The inner cylinder is perforated to
allow sand to fall into the space between the inner and outer cylinders.
The inner cylinder includes an inner helical vane to urge sand, media, and
castings toward the outlet area, and an outer helical vane to urge sand
and media toward the inlet area. A reclassifying screen is provided in the
inlet area to classify sand. Sand particles that are sufficiently small
passes through the screen and out a chute. Sand particles that are not
small enough are recirculated through the tumbling mill to be further
broken down. A shell is positioned in the inlet area between the inner
cylinder and the screen to hold the segments which form the inner cylinder
together under heavy tumbling. The shell includes a plurality of
relatively large openings to allow any sand that falls enters the shell to
fall through to the screen. A third helical vane is positioned between the
shell and the screen. Preferably, the edges of the third helical vane are
aligned with the openings in the shell. The shell is sufficiently thick
(preferably between 3/8" to 1") to prevent said segments from separating
under pressure of extensive tumbling.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view, partially cut away, of a tumbling unit of the
present invention;
FIG. 2 is a cross-sectional view unit taken through an inlet area of the
unit; and
FIG. 3 is a side elevational view of an inlet area of the tumbler, partly
in cross-section, with the outer cylinder of the tumbler removed.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A tumbler 1 of the present invention is mounted on a base 3. As described
in my above noted patents, the base 3 includes a motor which rotationally
drives the tumbler 1. The tumbler 1 includes an inlet 5 and an outlet 7,
It comprises an outer cylinder 9 having an inner cylindrical liner 11
supported concentrically within the outer cylinder 9. The liner 11 has
perforations 13 and is formed of segmented modular components that are
sectionalized and fitted together to form the liner 11. A helical vane 15
is formed on the inner surface of the liner 11 and a second helical vane
17 is formed on the outer surface of the liner 11.
Preferably, a chute or conveyor 18 is provided at the inlet 5 of the
tumbler to deliver castings, media, and sand into the tumbler. As
discussed in my prior patents, the inner vane or rifling 15 tends to urge
the castings, media, and sand toward the outlet 7 of the tumbler 1. Along
the way, the sand falls through the perforations 13 in the liner 11 of the
tumbler. At the outlet 7 of the tumbler 1, the remaining sand and media
falls through larger perforations 20, and the castings exit the tumbler.
The outer vanes 17 of the liner 11 operate to urge the sand and media back
toward the inlet 5 of the tumbler.
The tumbler inlet 5 is provided with an intake paddle wheel or lifts 19 and
a recirculation wheel 21. The recirculation wheel 21 is secured to the
liner 11 and the intake wheel 19 is secured to the recirculation wheel.
Thus, the intake wheel 19 and the recirculation wheel 21 rotate with the
inner liner 11. The recirculation wheel 21 includes an outer or front wall
23 which stops the reverse flow of the sand and media. A series of paddles
or lifts 25 in the recirculation wheel 21 carries the media and sand up,
and when the vane is tilted, due to rotation of the wheel, the sand and
media fall off the recirculation wheel paddles and onto the chute to be
reintroduced into the tumbler 1.
The inlet area of the tumbler is provided with a dust collection hood 31
having a sand chute 33. A perforated screen 35 surrounds the liner 11 in
the inlet area. The screen perforations are sized to allow a desired size
of sand particle through the screen. The classified sand falls through the
screen and down the chute for collection. The larger sand particles and
the media are then reintroduced into the tumbler. This allows for the
recirculation of the media, and further reduction of the size of the sand
particles.
In prior sand reclaiming tumblers, such as shown in my above noted patent,
U.S. Pat. No. 5,267,603, the liner 11 in the inlet area is substantially
unsupported. There is thus nothing to support or reinforce the inlet where
the liner segments separate the sand from the media. In the remaining
sections of the tumbler, the outer vanes 17 extend substantially the
distance between the outer cylinder 9 and the liner 11. Thus, the outer
cylinder 9 supports the liner throughout the remaining sections of the
tumbler. In the prior tumbler, the screen 35 directly surrounded the liner
11. However, under certain circumstances, the screen 35 may not be
sufficient to support the liner, and the liner 11 may begin to separate.
The tumbler of the present invention is thus provided with a shell 37 in
the inlet area. The shell 37 directly surrounds the liner 11 to hold the
liner 11 in its cylindrical configuration. The shell 37 is much sturdier
than the screen 35, and is preferably made of 3/8" to 1" plating, whereas
the screen is much thinner. The screen 35 is spaced from the outer surface
of the shell 37 by a third helical vane 39. Unlike helical vanes 15 and
17, which extend substantially the length of the tumbler, helical vanes 39
extend only the length of the inlet area.
The shell 37 has a diameter substantially equal to the outer cylinder 9.
Thus, the media and sand which fall through the liner 11 will end up on
the inner surface of the shell 37. To allow the sand and media to be
classified by the screen 35, the shell 37 is provided with a plurality of
openings 41. The openings can be any desired size and shape. Preferably,
they are rectangular and have are about 4".times.9" in size. As can be
seen in FIG. 3, the openings 41 and vanes 39 are positioned such that the
edge of the vanes 39 line up with the edge of the openings 41. Preferably,
the edges of the vanes 17 also line up with the edge of the openings 4 1.
This will ensure that a majority of the sand will fall through the shell
37 to be classified by the screen 35.
As variations within the scope of the appended claims may be apparent to
those skilled in the art, the foregoing description is set forth only for
illustrative purposes and is not meant to be limiting.
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